Speedometer.



W. G, LEATHERSJ SPEEDOMETER. APPLICATION-FILED Aue.8. 1912.

Jilly 20,1915. HEETS-SHEET I.

' Patented Wifk W. G. LEATHERS.

SPEEDOMETER.

APPLICAIIOH FILED Aue.8. I912.

Patented July 20,1915.

2 SHEETS-SHEET nWmro/e WIT/V359 I WARD G. LEATHERS, OF'NEW YORK, N. Y.,ASSIGNOR TO STEWART-WARNER SPEED- OMETER CORPORATION, OF CHICAGO,ILLINOIS, A CORPORATION OF VIRGINIA.

SPEEDOMETER.

Specification of Letters Patent.

Application filed August 8, 1912. Serial No. 714,128.

To all whom it may concern: Be it known that I, WARD G. LEATHERS, acitizen of the United States, residing in the city of New York, boroughof Manhattan, county and State of New York, have invented a certain newand useful Speedometer, of which the following is a specification.

. This invention is a speedometer, the same being particularly adaptedfor use on motordriven vehicles, such as automobiles.

The speedometers now in use on automobiles are characterized chiefly bythe use of indicating members, the figures and graduations of which areso small in size that they cannot be read without requiring fixedattention by the driver. As is well known, the indications given out bya speedometer vary or fluctuate within wide limits, particularly when anautomobile is traveling through the streets of a city or village, suchvariation being due to the necessity for slowing down the automobile atstreet crossings, to stop in order that other vehicles and pedestrlansmay cross a roadway, to reduce the D illustrated one practicalembodiment of the speed in compliance with the legal speed requirements,etc. Owing to such variations in the speed, the driver is required toconstantly watch the instrument, but when it is considered that thedriver must also give strict attention to the road ahead, and tomanipulate various levers for controlling the clutch and brake of themachine, as well as to give warning signals, it will be apparent thatvery little time can be deyoted to inspecting the speedometer readm s.

The object of the invention is to 'enable the driver to read the speedindications by merely glancing at the instrument, and, furthermore, tosimplify the device as to render it compact, efficient and reliable.

The invention, in a broad aspect, embodies indicating means the numbersof which represent the speed at which the machine is travelin and whichnumbers vary with the speed 0 the car, in combination with means forenlarging the numbers of said indicating means to the end-that thereadings will be plainly visible to the driver, whereby a relativelysmall and compact instrument is produced and one which the driver caninspect 'without requiring fixed attention, thus leaving the driver freeto give attention to the manifold duties required in the operation ofthe car.

The invention consists further ofa band or ribbon of translucent,fiexible material, preferably celluloid, which'contains a figure for theindicating of each mile per hour of speed from zero to the maximumcapac- 1ty of the instrument such as 60, 8% or 100 miles. This band orribbon is used in combination with a means for imparti n a Patented ul2o, 1915.

forward movement to it in proportion to the speed of the vehicle, andwith a retar mg force preferably a spring for the purpose ofreturning-it to zero. It is also provided with a means for making thatmovement intermittent so that one number at a time appears before theobserver. This in-. termittent mechanism is in no way necessary to thesuccessful working of theinstrument. p a

All the above will be hereinafter more fully explained.

Other features of-the invention and the advantages thereof will appearin the annexed detailed description. 7

In the accompanying drawing I have invention, but the construction showntherein is to be understood as illustrative only,

and not as defining the limits of the invenvehicle. Fig. 2 is a verticalcross section of the instrument taken at the line 1--1 of Fig. 1 andshows in the main its working parts. Fig. 3 is a section of the ribbonor translucent band about actual size- Fi 4.

is a horizontal crosssection taken at 'the ine I 2'2 of Fig. 2 as seenfrom the rear. Fig. 5 is a perspective view of the drum'E showing themagnetic means of obtaining the intermittent movement. Fig. 6 is theperspective view of a shield for limiting the field of visionand may beused in place of the lens-tube.

The several working parts are housed within a substantially dust-tightcasing composed mainly of two sections A and A,

said sections being separately coupled to-' gether in any suitable Way.

The form and size of-the members composing the casing may be variedwithin wide limits but it is preferred to employ the shape shown, as itvery compactly houses the mechanism.

The upper portion of the case is amodiher A is associated a lens-tube B,the latter extending into the chamber of the easmg and terminatlng asuitable distance above the lndicating mechanism; the mam function ofsaid lens-tube being to limit the field of vision at any particularmoment.

As shown, the lens-tube tapers from its upper to its lower extremity andis mounted or supported within the upper aperture of easing member A,and the lens B is secured in the upper part of said lens-tube. Obviouslythe particular manner of supporting the lens and the lens-tube may bemodified by a skilled constructor.

Within member A of the casing is a fixed frame member C which may be inthe form of a modified ellipse with numerous projectlons for supportingthe bearings shown vmore particularly in Fig. 4.

Within the main cavity surrounded by the casing member A are twocylindrical drums, D and E of approximately similar diameter. Thesedrumsare supported on bearings and furnished with flared rims for thepurpose of guiding and supporting the translucent ribbon F which isrolled from one drum to the'other and back again when the vehiclestarts, goes, and stops. (The ribbon is not shown in Fig. 4.)

At GGGG will be seen the guide rolls which maintain the proper distancebetween the translucent ribbon and the lens tube keeping the indicatingmeans always at the proper focal distance from the lens.

This speedometer is provided with an electric light and reflector shownat H from which position it throws its rays through the translucentindicating ribbon.

The drum D surrounds the revolving permanent magnet I which furnishesthe motive force. The magnet I is driven by the usual method. Itis'monnted on the end of a shaft S supported in bearings T and attachedto a flexible shaft U carried in a flexible tube and geared to one ofthe wheels oi. the we hicle.

As is well known, as the magnet I re volves the magnetic torque producedon the drum D increases or decreases in propor tion to the speed of themagnet I. As the drum .1) turns in the direction of the arrow, it windsabout its periphery the translucent ribbon containing the indicatingfigures. As the drum D revolves and rolls the ribbon about itself, it isnecessary for the cylinder E to revolve in the same direction as it paysout the ribbon.

When the magnet .l is not revolving, that being when the vehicle is notin motion,

mar/see nearly all of the translucent ribbon is wound around theperiphery of the drum E. in-

side the drum in is provided a long, sensi tive, coil spring J, thepurpose of which is to return the indicatingmechanism to Zero. One endof the spring J is made fast in permanent position by the finger N.

In Fig. 5, may be seen the means for ob taining an intermittent movementby means of which one figure, corresponding to a given number of milesper hour traveled by the vehicle, is directly beneath the lenstube. K isa permanent horse-shoe magnet fastened to the frame C by means of thescrew L or by any other suitable means. The ends of the magnet areadapted to hold small,soft iron pieces R in the center of their magneticfield. These small iron pieces are attached to the drum E and re volvewith it, and are arranged at equal intervals as nearly as possiblecorresponding to the distance between the indicating figures-onthe-ribbon.

In Fig. 3 may be seen a section of the translucent ribbon approximatelyactual size. Figures" are shown which indicate speed of 22 to 26 milesper hour. Surrounding the figure 24 may be seen a ring B whichcorresponds to the lower end of the lens tube B. The figures on theribbon corresponding each to a given speed are arranged at suchintervals as will cause them to stop directly beneath the lens-tube whenthe soft iron pieces come directly beneath the points of the permanentmagnet K.

Other means than the lens-tube may be used for restricting the vision toapproximately a single reading and as one of the many possiblemodifications I present the shield shown in Fig. 6 wherein the readingis made through the aperture M.

While I have indicated and described a magnetic device operated by aflexible shaft for imparting movement to the magnet ll, it is evidentthat any of the usual mechanically driven devices may be substitutedtherefor.

Havin g thus fully described the invention, what i claim as new, anddesire to secure by Letters Patent is:

1. in speedometer the combination of indicating means comprising a bandprovi ded with characters for denoting the speed of a. vehicle, andmeans for actuating the indicating means to change the position of thelatter with the speed of the vehicle, comprising drums to which the endsof the band are connected, magnetic means acting to wind. the band onone drum and a coil spring on the shaft of the other drum acting to windit up thereon.

2. in a speedometer the combination of movable indicating means providedwith characters for denoting the speed of a vehicle and arranged insequential indicating position, and means to move the indicating meansto change the position of the latter .\;th the speed of the vehicle,comprising magnetic means to yieldingly'force the indicating means fromone of its indications to another, and means tending to retain theindicating means in a fixed position by tending to prevent movementthereof forwardly and backwardly.

3. In a speedometer the co1nbination of movable indicating meansprovided with characters for denoting the speed of a vehicle andarranged in sequential indicating positions, means to move theindicating means to change the position of the latter with the speed ofthe vehicle, comprising magnetic means to yieldingly force theindicating means from one of its indications to another, and a fixedmagnet and a body of magnetic material supported so as to be movablewith the indicating means tending to retain the indicating means in afixed position.

4. In a speedometer the combination of movable indicating means providedwith spring tending to move it in the other direction, to yieldinglyforce the indicating means from one of its indications to another, andmeans tending to retain the indicating means in afixed position bytending to prevent movement thereof forwardly and backwardly.

5. In a speedometer, the combination of movable indicating meansprovided with characters for denoting the speed of the vehicle andarranged in sequential indicating positions, means to move theindicating means to change the position of the latter with the speed ofthe vehicle, comprising a rotatable magnet tending to move theindicating means in one direction and a coiled spring tending to move itin the other direction, toyieldingly force the indicating means from oneof its indications to another, and a fixed magnet and body of magneticmaterial supported so as to be movable with the indicating means andtending to retain the indicating means in a fixed position. y

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

WARD G. LEATHERS.

